diff --git a/python/cosmotool/simu.py b/python/cosmotool/simu.py
index 8aa7722..3dd4cf6 100644
--- a/python/cosmotool/simu.py
+++ b/python/cosmotool/simu.py
@@ -1,3 +1,4 @@
+import warnings
 from _cosmotool import *
 
 class SimulationBare(PySimulationBase):
@@ -18,6 +19,10 @@ class SimulationBare(PySimulationBase):
     self.Hubble = s.getHubble()
     self.Omega_M = s.getOmega_M()
     self.Omega_Lambda = s.getOmega_Lambda()
+    try:
+      self.masses = s.getMasses().copy() if s.getMasses() is not None else None
+    except Exception as e:
+      warnings.warn("Unexpected exception: " + repr(e))
   
   
   def merge(self, other):
@@ -48,6 +53,11 @@ class SimulationBare(PySimulationBase):
     self.positions = _safe_merge(self.positions, other.getPositions())
     self.velocities = _safe_merge(self.velocities, other.getVelocities())
     self.identifiers = _safe_merge0(self.identifiers, other.getIdentifiers())
+    try:
+      self.masses = _safe_merge0(self.masses, other.getMasses())
+    except Exception as e:
+      warnings.warn("Unexpected exception: " + repr(e));
+      self.masses = None
     
   def getPositions(self):
     return self.positions
@@ -58,6 +68,9 @@ class SimulationBare(PySimulationBase):
   def getIdentifiers(self):
     return self.identifiers
 
+  def getMasses(self):
+    return self.masses
+
   def getTime(self):
     return self.time